The present invention concerns a novel system for supplying and/or storing purified water.
Systems for supplying purified water are widely used today in residences, officers and factories. In one type of purified water supply system, as disclosed in Bray, et al. U.S. Pat. No. 3,493,496, unpurified water is directed to a reverse osmosis unit. The product water from the reverse osmosis unit is directed to an accumulator tank for storage. In the Bray et al. system, a pressure differential is always maintained across the reverse osmosis membrane. To accomplish the maintenance of the pressure differential across the reverse osmosis membrane, a pressure relief valve is used so that when a certain pressure is reached within the accumulator tank the pressure relief valve will cause the product water to be directed to drain.
It can be seen that the Bray et al. system requires continuous flow of water, and it is believed that this continuous flow overcomes the osmotic and bacteriological problems created in the water that is standing between the reverse osmosis membrane and the accumulator tank if there was no continuous flow.
While the flow of water into the accumulator tank is useful, the use of a pressure relief valve to direct water to drain once the accumulator tank is filled, is wasteful of water, provides a constant noise, and is illegal in certain regions.
In order to obviate the difficulties concomitant with a continuous flow of product water, another type of purified water supply system utilizes a shutoff valve which automatically shuts off the flow of water to the reverse osmosis unit once the accumulator tank has reached a certain pressure. The disadvantage of this system, however, is that there may be bacteriological and osmotic problems in the water that has been standing between the reverse osmosis unit and the accumulator tank.
In Tyler et al. U.S. Pat. No. 4,391,712 a reverse-osmosis water purifier apparatus is disclosed which does not require continuous flow of the product water and which enables a first quantity of water from the reverse-osmosis filter to flow to drain. However, Tyler et al. requires the use of a hydraulic accumulation tank to divert the first quantity of water from the reverse-osmosis filter which may be expensive, complex and bulky.
I have discovered a system in which the aforementioned problems concomitant with continuous flow and also the aforementioned problems concomitant with the use of a shutoff valve are alleviated, without requiring the use of a hydraulic accumulator tank to divert the first quantity of water.